System and method for rehabilitating a host pipe

ABSTRACT

A system for in situ rehabilitation of a corrugated culvert or other conduit includes a support frame coupled to an inner surface of the culvert. The support frame provides attachment points that are spaced away from the inner surface of the culvert. An assembly of interconnected longitudinal planks is coupled to the support frame and forms a liner within the culvert. Each longitudinal plank has an inwardly facing surface that forms a portion of an inner surface of the liner and an outwardly facing surface opposite the inwardly facing surface. At least one longitudinal protrusion extends away from the outwardly facing surface of each longitudinal plank. A layer of a cured cementitious grout material fills or substantially fills a space between the inner surface of the host pipe and the plurality of interconnected planks, and the at least one longitudinal protrusion of each longitudinal plank is embedded within the cured cementitious grout material.

REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. Provisional Patent Application No. 63/139,085 filed on Jan. 19, 2021; Canadian Patent Application No. 3,112,125 filed Mar. 17, 2021; and Canadian Patent Application No. 3,125,165 filed Jul. 20, 2021, all of which are incorporated herein by reference in their entirety.

FIELD

This disclosure relates generally to water-management infrastructure such as pipes and corrugated steel culverts, and more particularly to an environmentally benign system and method for rehabilitating and extending the useful life of such infrastructure.

BACKGROUND

For over a century, more than a third of the drainage culverts installed in the United States have been corrugated steel pipe (CSP) in round and pipe-arch shapes. The service life of a corrugated metal culvert varies, depending on factors such as coatings, material thickness, climate, maintenance, pH on water flows, and the condition of the surrounding soil. Since this type of culvert came into widespread use by the 1950s, many are now reaching the end of their useful life and need to be repaired, replaced, or refurbished before they fail. Metal culverts can fail in different ways. For example, rust and corrosion can cause the pipe to leak, or even disintegrate and collapse. Leaks can lead to erosion around the pipe and the resulting lack of structural support can cause the pipe to break, often unexpectedly. Pipe failure can wash out roads and bridges and cause environmental damage to the waterways they drain into.

Of course, culverts can be replaced by building a new culvert close to the existing one or by digging up the existing pipe and replacing it. Unfortunately, these methods can be very costly and time-consuming. Further, open cut methods may be impractical due to the impact they have on vehicular traffic, since the road above the culvert will likely have to be closed during culvert replacement, or because of limitations imposed by terrain, and/or climate.

Culverts can sometimes be rehabilitated without digging them up using a process that is referred to in the industry as trenchless replacement technology. In this method, a new pipe is attached to a tool that is pushed or pulled through the existing damaged pipe. The tool head intentionally breaks or splits the old pipe as it drags the new liner pipe behind it, and therefore this technique is also referred to as “pipe bursting.” Such trenchless methods allow culverts to be replaced with minimal disruption to traffic flow on the roadways above the culvert and with less impact on the waterways the culvert drains into. However, such “pipe bursting” techniques are “destructive” to the pre-existing host pipe, i.e., the culvert that is being replaced, thereby rendering the host pipe effectively useless for providing support or peripheral protection, for example, to the new liner pipe.

Another technique for rehabilitating old culverts is to use a slipliner, wherein a plastic liner is pulled through the interior of the host pipe without breaking it. Unfortunately, difficulties may be encountered with pulling the liner through a corrugated pipe, especially if the pipe is damaged or partially collapsed. The process of pulling the plastic liner through the pre-existing host pipe also places the liner under strain, which may weaken the liner and lead to premature failure.

Yet another technique for rehabilitating old culverts is to use a technology called cured in place pipe, or CIPP. In this technique a wet lining is pulled in place and then induced to harden in the field. Unfortunately, some CIPP materials and their installation methods can pose environmental risks, including the release or leaching of toxic materials into the environment, which has been known to cause fish kills, negatively affect wastewater treatment plants, and has even resulted in daycare center, school, and government building evacuations.

As will be apparent, rehabilitating damaged culverts, heretofore, has been difficult. Furthermore, the environmental cost of replacing rusted, corroded, or damaged metal corrugated steel pipes (CSPs) in the form of culverts is extremely large due to their prevalence throughout the United States and other countries around the world. Many solutions have been proposed but none are entirely without drawbacks including negative impacts on fish, wildlife, plant life, soil, and water in and around the culvert that is being rehabilitated. It would therefore be beneficial to provide a system and method that overcomes at least some of the above-mentioned drawbacks.

SUMMARY OF EMBODIMENTS

In accordance with an aspect of at least one embodiment, there is provided a method for in situ rehabilitation of a host pipe, comprising: disposing a support frame within the host pipe and adjacent to an inner surface of the host pipe, the support frame providing a plurality of attachment points spaced away from the inner surface of the host pipe; attaching a plurality of longitudinal planks to the support frame via the plurality of attachment points, each longitudinal plank of the plurality of longitudinal planks having an inwardly facing surface that forms a portion of a liner surface within the host pipe, and each longitudinal plank of the plurality of longitudinal planks having an outwardly facing surface opposite the inwardly facing surface with at least one longitudinal protrusion extending away therefrom; and at least partially filling a space that is defined between the inner surface of the host pipe and the plurality of longitudinal planks with a cementitious grout material, to form a grout layer upon curing of the cementitious grout material, wherein the cementitious grout material flows around and surrounds the at least one longitudinal protrusion during the step of filling the space, such that the at least one longitudinal protrusion is embedded within the grout material upon curing of the cementitious grout material.

In accordance with an aspect of at least one embodiment, there is provided a method for in situ rehabilitation of a host pipe in the form of a corrugated culvert or other conduit, comprising: applying a preparation treatment to an inner surface of the host pipe to at least partially fill in at least some corrugated indentations in the inner surface of the host pipe; disposing a support frame within the interior of the host pipe and adjacent to the host pipe inner surface, and coupling said support frame to the host pipe; assembling a plurality of longitudinal planks within the interior of the host pipe to form a liner, comprising attaching the longitudinal planks to the support frame and further comprising coupling together adjacent longitudinal planks via coupling structures that are arranged along each of the opposite longitudinal edges of each of the longitudinal planks, wherein each longitudinal plank has an inwardly facing surface that forms a portion of an inner surface of the liner and an opposite outwardly facing surface having at least one longitudinal protrusion extending away therefrom; and, at least partially filling a space that is defined between the preparation treatment applied to the inner surface of the host pipe and the assembled plurality of longitudinal planks with a cementitious grout material, to form a grout layer upon curing of the cementitious grout material, wherein the cementitious grout material flows around and surrounds the at least one longitudinal protrusion during the step of filling the space, such that the at least one longitudinal protrusion is embedded within the grout material upon curing of the cementitious grout material.

In accordance with an aspect of at least one embodiment, there is provided a system for in situ rehabilitation of a host pipe in the form of a corrugated culvert or other conduit, comprising: a support frame, which is sized for being received within and coupled to an inner surface of the host pipe, the support frame configured to provide a plurality of attachment points spaced away from the inner surface of the host pipe; a plurality of interconnected longitudinal planks forming a liner within the host pipe, each longitudinal plank of the plurality of longitudinal planks having an inwardly facing surface that forms a portion of an inner surface of the liner, and each longitudinal plank of the plurality of longitudinal planks having an outwardly facing surface opposite the inwardly facing surface with at least one longitudinal protrusion extending away therefrom; and a layer of a cured cementitious grout material filling or substantially filling a space between the inner surface of the host pipe and the plurality of interconnected planks, wherein the at least one longitudinal protrusion of each longitudinal plank is embedded within the cured cementitious grout material.

In accordance with an aspect of at least one embodiment, there is provided a rehabilitated culvert, comprising: a corrugated steel pipe (CSP) having an outer corrugated surface and an inner corrugated surface; a preparation treatment applied to the inner corrugated surface; a layer of cured cementitious grout material bonded to the preparation treatment; a support frame embedded within the layer of the cementitious grout material; and a plurality of interconnected longitudinal planks arranged side-by-side and end-to-end, each longitudinal plank having at least one longitudinal protrusion on a surface thereof facing the inner corrugated surface, the at least one longitudinal protrusion of each longitudinal plank being imbedded within the layer of cured cementitious grout material, the interconnected longitudinal planks cooperating to form an inside liner of the CSP that is spaced away from the inner corrugated surface of the CSP.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments will now be described in conjunction with the drawings in which:

FIG. 1A is an isometric view showing a host pipe, in the form of a corrugated steel tube, after being rehabilitated using a system according to an embodiment of the invention.

FIG. 1B is a corresponding end view of FIG. 1A.

FIG. 2A is an isometric view showing a host pipe with a prepared inner surface.

FIG. 2B is an enlarged partial view taken within the upper left rectangle in FIG. 2A.

FIG. 2C is an enlarged partial view taken within the lower right rectangle in FIG. 2A.

FIG. 3A is an isometric view showing a support frame in the form of a hoop-and-rod rebar structure.

FIG. 3B is an enlarged partial view of the support frame of FIG. 3A, showing clip connections between the hoop elements and rod elements of the support frame.

FIG. 4 is an isometric view showing an assembly of longitudinal planks.

FIG. 5A is an isometric view showing the outer surface of an exemplary longitudinal plank.

FIG. 5B is an end view of the longitudinal plank of FIG. 5A.

FIG. 6A is an isometric view of an end connector for joining together curved longitudinal planks.

FIG. 6B is an isometric view of an end connector for joining together flat longitudinal planks.

FIG. 7A is an enlarged partial view showing detail within the upper dashed-line box of FIG. 1B.

FIG. 7B is an enlarged partial view showing detail within the lower dashed-line box of FIG. 1B.

FIG. 8A is an isometric view showing a host pipe, in the form of a corrugated steel tube, after being rehabilitated using a system according to another embodiment of the invention.

FIG. 8B is a corresponding end view of FIG. 8A.

FIG. 9A is an isometric view showing a support frame in the form of a double rebar-coil structure.

FIG. 9B is an enlarged partial view showing detail within the dashed-line box of FIG. 9A.

FIG. 10A is an enlarged partial view showing detail within the upper dashed-line box of FIG. 8B.

FIG. 10B is an enlarged partial view showing detail within the lower dashed-line box of FIG. 8B.

FIG. 11 is an enlarged partial view showing detail within the dashed-line box of FIG. 10A.

FIG. 12 is an isometric view showing the clip mechanism and wedge mechanism mounted to the outer surface of a longitudinal plank.

FIG. 13 is an isometric view showing the clip mechanism in isolation.

FIG. 14A is an isometric view showing the wedge mechanism in isolation.

FIG. 14B is a cross-sectional view of the wedge mechanism taken along the plane P_(cross) in FIG. 13A.

FIG. 15 is a simplified flow diagram of a method according to an embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS

While the present teachings are described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments. On the contrary, the present teachings encompass various alternatives and equivalents, as will be appreciated by those of skill in the art. All statements herein reciting principles, aspects, and embodiments of this disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.

As used herein, the terms “first”, “second”, and so forth are not intended to imply sequential ordering, but rather are intended to distinguish one element from another, unless explicitly stated to the contrary. Similarly, sequential ordering of method steps does not imply a sequential order of their execution, unless explicitly stated.

FIG. 1A is an isometric view of a system according to an embodiment, shown in an installed condition within a host pipe 100 in the form of a corrugated steel tube. FIG. 1B is a corresponding end view of the system that is shown in FIG. 1A. Although it is not shown explicitly in FIG. 1A or FIG. 1B, the host pipe 100 is partially buried in the ground and is surrounded typically by soil, clay, or an aggregate material such as for instance sand and/or gravel. For example, the host pipe 100 may be installed substantially horizontally beneath a not-illustrated highway, with the opposite ends thereof projecting from the roadbed, for providing water drainage under the highway or for providing a wildlife corridor, etc. The size of the host pipe 100 may be in a range from less than a meter to several meters in diameter with typical lengths that are greater than several meters. A very long host pipe 100, having a length greater than e.g., 10 meters, may be fabricated using a series of shorter pipe-sections that are connected in an end-to-end fashion to provide a desired final length. The method and system described herein is equally suited for use with host pipes that are fabricated from either a single length of pipe or several connected lengths of pipe.

Installation of the system that is shown in FIG. 1A and FIG. 1B is performed with the host pipe 100 remaining in place, resulting in a new liner being formed within the pre-existing host pipe 100. Since the host pipe 100 is not removed or broken during the installation process, the disruption to vehicle traffic, wildlife, and the surrounding environment is minimized. Advantageously, the system that is shown in FIG. 1A and FIG. 1B provides mechanical support to prevent partial collapse or total failure of the pre-existing host pipe 100, whilst also minimizing or eliminating further erosion around the host pipe 100. Once installed, the system that is shown in FIG. 1A and FIG. 1B may extend the useful life of the host pipe 100 by an additional 75 years by providing wall restoration, waterproofing, and/or abrasion resistance.

Referring still to FIG. 1A and FIG. 1B, the system according to the instant embodiment includes different components, which may be envisaged as being arranged in distinct layers that are assembled within the pre-existing host pipe 100 in a series of steps. The number of these different components and their specific configuration may vary depending upon the type of host pipe 100 that is being rehabilitated, the condition of the host pipe 100, and the size of the host pipe 100, etc.

Prior to rehabilitating the host pipe 100, the surrounding site conditions should be surveyed to identify abnormalities or additional problems that may exist on site and appropriate remediation steps should be taken. Optionally but preferably, a LIDAR (Light Detection and Ranging) survey should be conducted to record initial conditions to be compared with conditions that are measured after rehabilitation is complete. Key survey points to be studied are at, for example, 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock positions within the host pipe 100. Of course, different positions and/or additional positions may be surveyed.

After completing the initial survey, for best results, the inner surface of the host pipe 100 is cleaned using e.g., high pressure water blasting to remove bond breaking substances disposed thereon. For instance, a water pressure of at least 3000 psi and more preferably at least 5000 psi may be used for the initial cleaning step. Now referring also to FIG. 2A, after the inner surface of host pipe 100 has been cleaned resilient anchoring fasteners 202 may be attached thereto. For example, high-density polyethylene (HDPE) or Basaltic bar ties are affixed to the inner surface of the host pipe 100 at 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock positions and are spaced along the length of the host pipe 100 that is to be repaired or refurbished. Optionally, additional anchoring fasteners 202 are attached to the inner surface of host pipe 100 between the above-mentioned circumferential positions, with the number of fasteners 202 in both the circumferential direction and the length direction depending on factors including the size of the host pipe 100.

In this specific and non-limiting example, a preparation treatment 200 is applied to an inner surface of the host pipe 100. As is shown most clearly in FIG. 2B, the preparation treatment 200 at least partially fills the inner corrugations or indents along the inner surface of the host pipe 100. The preparation treatment 200 may be applied around the entire inner circumference of the inner surface as shown in FIG. 2A, or optionally the preparation treatment 200 may be applied to only a portion of the inner circumference of the inner surface, such as for instance between about the 5 o'clock position to about the 7 o'clock position.

Now referring also to FIG. 2C, the preparation treatment 200 may include a plurality of different materials, which are applied in a plurality of separate layers. In the example that is shown in FIG. 2C, a layer of closed cell foam 204 is applied initially to the inner surface of the host pipe 100. Preferably, the inside diameter of the host pipe 100 is substantially uniform along the length thereof after application of the closed cell foam 204. The term “substantially uniform” in this context means more uniform than the diameter of the host pipe before applying the closed cell foam 204, since the corrugation indents are at least partially filled in. Preferably 80% to 100% of the depth of corrugation indents of the inner surface of host pipe 100 are filled in after this step, and more preferably the layer of closed cell foam is screeded to a substantially circular cross-section. A layer of a mortar material 206, such as for instance repair mortar VELOSIT® RM 202, is then applied on top of the closed cell foam 204 using a trowel or another suitable applicator. Finally, in the instant example, a waterproof layer 208, such as for instance VELOSIT® WP 120, is applied. As shown in FIG. 2C, a gauge pin 210 may be installed prior to application of the above-mentioned layers of material to guide the application and screeding of the closed cell foam 204. The thickness of the layer of closed cell foam 204 varies along the length of the host pipe 100 due to the irregular shape of the inner surface of the corrugated material of the host pipe 100. Suitable thicknesses of the layers of repair mortar layer and of the waterproof layer are approximately 6 mm and 2 mm, respectively.

In an alternative implementation, the preparation treatment 200 may be formed entirely from the repair mortar VELOSIT® RM 202 or another suitable material, optionally with a waterproof layer applied on top thereof. The repair mortar or other suitable material in this case serves to fill in the corrugation indents and to provide the bonding surface to which another cementitious grout material can adhere during subsequent steps of the installation process. Advantageously, the layer of repair mortar or other suitable material filling the corrugation indents is structurally strong and increases support within sections of the host pipe 100 that are badly corroded or damaged.

Referring again to FIG. 1A and FIG. 1B, the host pipe 100 is shown with a layer of cement 102 at the 6 o'clock position. The purpose of applying this layer of cement 102 is to provide additional thickness and to obviate the corrugations as this is the location where liquid typically runs and sits and is most likely to corrode the material of the host pipe 100.

The system shown in FIG. 1A and FIG. 1B further includes a support frame 300, which is shown in isolation in FIG. 3A. The support frame 300 is anchored to the host pipe 100, e.g., via the previously attached resilient anchoring fasteners 202. Of course, the support frame 300 may be anchored in different ways but should be substantially unable to move during the installation procedure. Once installation is complete, the support frame will be embedded within a layer of a cured cementitious material which will prevent movement of the support frame even if the anchoring fasteners 202 fail.

The support frame 300 may be formed in a single continuous section or alternatively it may be formed in a plurality of sections that are arranged end-to-end, with each section including rod elements 302 (e.g., 6 m lengths of 10 mm rebar arranged at 3 o'clock, 6 o'clock, 9 o'clock, and 12 o'clock positions within the host pipe 100) and hoop elements 304 that are spaced approximately 300 mm apart. The support frame 300 may be fabricated from common construction materials, such as for instance steel rebar, in which case the rod elements 302 and hoop elements 304 may be welded together, during installation within the host pipe 100, to form the support frame 300. Alternatively, the rod elements 302 and the hoop elements 304 may be clipped and secured in place, to form the support frame 300 without the need for welding, using clips 306 as shown most clearly in FIG. 3B, or using other suitable ties or fasteners. As discussed above, once installation is complete the support frame 300 will be embedded within a layer of a cured cementitious material which will prevent movement of the support frame including relative movement of the rod elements 302 and hoop elements 304, even if the clips 306 fail.

Additional rod elements 308, which optionally may have a diameter smaller than that of the rod elements 302, may be arranged at 1 o'clock, 2 o'clock, 4 o'clock, 5 o'clock, 7 o'clock, 8 o'clock, 10 o'clock, and 11 o'clock positions within the host pipe 100, or at another suitable spacing depending on the diameter of the host pipe 100. As shown in FIG. 3B, the additional rod elements 308 may be anchored to the inner surface of the host pipe 100 using anchors 310 and clipped to the hoop elements 304 using clips 312.

The support frame 300 provides a plurality of attachment points along a curved plane that is spaced away from the inner surface of the host pipe 100. As shown in FIG. 1B, the spacing between the support frame 300 and the preparation treatment 200 on the inner surface of the host pipe 100 may vary in the circumferential direction. For instance, the support frame may be constructed such that there is a larger space at the bottom of the host pipe 100, which is partially filled by the layer of cement 102.

Now referring also to FIG. 4, the system that is shown in FIG. 1A and FIG. 1B further includes an assembly 400 of longitudinal planks 402, the layer 400 being secured to the support frame 300 via the plurality of attachment points. As shown in FIG. 4, the assembly 400 of longitudinal planks 402 includes a plurality of individual planks 402 each having dimensions of, for instance, 1.2 m (4 feet) in length by 23 cm (9 inches) in width or 1.2 m (4 feet) in length by 30 cm (12 inches) in width, with a material thickness of about 4 mm (0.15 inches). Of course, the longitudinal planks 402 may have dimensions that differ from these specific and non-limiting examples, which have been selected to provide longitudinal planks that are of a manageable size such that one worker may lift, carry and install the longitudinal planks 402 as well as to allow the longitudinal planks 402 to be passed through narrow spaces or around obstacles and corners, etc. The longitudinal planks 402 are fabricated from a suitable material, which is preferably light-weight, for example a plastic or recycled plastic, such as for instance a high-density polyethylene (HDPE), using a suitable process, such as for instance an extrusion process.

Now referring also to FIG. 5A and FIG. 5B, each longitudinal plank 402 has a first face 404 and has a male coupling rail 406 formed along one longitudinal edge and a complementary female coupling groove 408 formed along an opposite longitudinal edge. When in an installed condition, the first face 404 is oriented facing toward the inner surface of the host pipe 100. Each longitudinal plank 402 has at least a protrusion extending from the first face 404. The protrusions perform several functions and may be provided in a variety of forms. For example, the protrusions may be provided as generally T-shaped longitudinal protrusions 410 a, 410 b and 410 c as shown in FIG. 5A. Although three longitudinal protrusions are shown in FIG. 5A, optionally the number of longitudinal protrusions may be less than three or greater than three. In addition, other protrusion profiles may be provided, such as for instance Y-shaped longitudinal protrusions or arrow-shaped longitudinal protrusions. In general, the longitudinal protrusions have a narrow cross-sectional profile proximate the first face 404 and a wide cross-sectional profile at some distance spaced away from the first face 404, wherein the cross-section is taken in a plane normal to the longitudinal direction of the longitudinal planks 402. In FIG. 5A each of the longitudinal protrusions 410 a, 410 b and 410 c, which are T-shaped, extends continuously between the two opposite ends of the longitudinal plank 402. Optionally one or more of the longitudinal protrusions is set back from one or both of the two opposite ends of the longitudinal plank 402. Further optionally, one or more of the longitudinal protrusions is not continuous along the length of the longitudinal plank 402, e.g., there are gaps between portions of the longitudinal protrusions.

The number, size, shape and orientation of the longitudinal protrusions is selected to be suitable for attaching the longitudinal planks 402 to the support frame via clips or other suitable fasteners, and for allowing cementitious grout material to flow around and embed the longitudinal protrusions therein after the cementitious grout material has cured, and to increase the torsional and/or longitudinal rigidity of the longitudinal planks 402 to resist movement and shifting during installation.

During installation of the system according to the instant embodiment, individual longitudinal planks 402 are placed side-by-side, with the male coupling rail 406 at the edge of one longitudinal plank being 402 slidingly inserted into and coupled with the complementary female coupling groove 408 at the edge of an adjacent longitudinal plank 402. The longitudinal male coupling rail 406 slides into the longitudinal recess of the female coupling groove 408 to form a grout-tight seal between the two longitudinal planks 402. The longitudinal planks are “locked” together when they are coupled in this fashion. However, the longitudinal planks can be “unlocked,” if necessary, before they are grouted in place by relatively sliding the longitudinal planks 402 in a reverse direction.

As shown most clearly in FIG. 5B, an opposite face 412 of each longitudinal plank 402 is substantially smooth. The substantially smooth opposite face 412 forms an inner liner-surface of the rehabilitated host pipe 100, and the smooth texture advantageously promotes flow of water within the host pipe 100 and avoids accumulation of debris such as plastic or paper litter, plant matter etc., due to the relative lack of liner surface features.

In the instant example, the longitudinal planks are curved in a direction transverse to their length. Since the cross-section of the assembly 400 of interconnected longitudinal planks 402 installed within the host pipe 100 will form substantially a circle, it is advantageous for the longitudinal planks 402 to have a slight curve conforming approximately to the curved wall of the host pipe 100, especially if the host pipe 100 is only a few meters or less in diameter. Alternatively, the longitudinal planks 402 are substantially flat and result in a polygon like cross-sectional profile that merely approximates a circle, especially when the diameter of the host pipe 100 is more than a few meters in diameter.

The assembly 400 of the longitudinal planks 402 may be built in stages, after the support frame 300 has been fully or partially assembled and suitably anchored inside the host pipe 100. A first plurality of the longitudinal planks 402 are fastened to some of the plurality of attachment points provided along the support frame 300. For instance, each attachment point is provided using a clip 1300, which is shown in isolation in FIG. 13. A first recessed portion 1302 of the clip 1300, which is generally circular in shape, is used to secure the clip 1300 to one of the rod elements 302 or 308 of the support frame 300. A second recessed portion 1304 of the clip 1300 is shaped to receive the free end of one of the T-shaped longitudinal protrusions 410 a, 410 b or 410 c of one of the longitudinal planks 402, thereby forming a connection between the longitudinal plank 402 and the support frame 300. Of course, the clip 1300 may be modified to connect different sized rod elements and/or different shaped longitudinal protrusions carried by the longitudinal planks 402. Advantageously, since the second recessed portion 1304 of the clip 1300 allows the clip 1300 to slide along the longitudinal protrusions on the longitudinal planks 402, the points of attachment between the longitudinal planks 402 and the support frame 300 can be adjusted to ensure that an adequate number of attachments are made, even if the support frame 300 is not built precisely to the expected specifications and/or the assembly 400 of longitudinal planks is not correctly aligned within the host pipe 100. In particular, the clip 1300 may be moved along the respective longitudinal protrusion to a point at which the first recessed portion 1302 is aligned with a suitable one of the rod elements 302 or 308 of the support frame 300.

Sliding-block wedges 1400, which are shown in isolation in FIG. 14A and 14B, optionally are positioned between the assembly 400 of longitudinal planks 402 and the support frame 300 or preparation treatment 200 on the inner surface of the host pipe 100. Each sliding-block wedge 1400 includes a body 1402 and a sliding wedge 1404, which slide relative to one another along an inclined plane P_(incl), as is shown most clearly in FIG. 14 B in a cross-section taken in the plane P_(cross) indicated in FIG. 14A. The body 1402 also has a channel 1406 that is sized to receive one of the T-shaped protrusions 410, 410 b or 410 c on the surface 404 of one of the longitudinal planks 402. Moving the sliding wedge 1404 relative to the body 1402 changes the effective thickness of the sliding-wedge block 1400 since the movement occurs along the inclined plane P_(incl). The sliding-block wedges may be disposed at different circumferential and longitudinal locations between e.g., the support frame 300 and the assembly 400 of longitudinal planks 402, to effectively shim the assembly 400 of longitudinal planks 402 in place. The sliding-block wedges 1400 also function to adjust the space that is defined between the assembly 400 of longitudinal planks 402 and the preparation layer 200, and to prevent movement of the assembly 400 of longitudinal planks 402 during subsequent steps in which a grout material is pumped into said space.

Of course, the sliding-block wedges 1400 may be omitted if the longitudinal planks 402 can be secured to the support frame 300 with sufficient rigidity to avoid significant movement or shifting during introduction of the cementitious grout material during subsequent steps. Alternatively, expanding ring-shaped support members may or other suitable reinforcement members may be temporarily installed within the assembly 400 of longitudinal planks to maintain a desired cross-sectional shape of the assembly 400 during introduction of the cementitious grout material. Once the grout material has cured, and the assembly 400 of longitudinal planks is locked into the desired configuration, the temporary support members may be removed. Further, the longitudinal planks 402 may be attached to the support frame 300 using other fasteners or differently configured clips.

Referring again to FIG. 4, a second plurality of the longitudinal planks 402 are then butted up against the ends of the first plurality of the longitudinal planks 402 and are secured to the support frame 300, so as to extend the length of the assembly 400 of longitudinal planks 402. A suitable end-coupling member is disposed between the ends of each longitudinal plank 402 of the first plurality of longitudinal planks 402 and the ends of each longitudinal plank 402 of the second plurality of longitudinal planks 402.

FIG. 6A shows detail of an end-coupling member 602 that is suitable for use with longitudinal planks 402 that are transversely curved, e.g., of the type that is shown in FIG. 4 and FIGS. 5A-5B. The coupling member 602 has a first end flange 604 and a second end flange 606 separated by a vertical wall 608. A generally U-shaped channel is formed along each side of the coupling member 602. When the coupling member 602 is disposed between the ends of two longitudinal planks 402, the end of one of the longitudinal planks 402 is received within the channel on one side of the coupling member 602 and the end of the other one of the longitudinal planks 402 is received within the channel on the other side of the coupling member 602.

FIG. 6B shows detail of an alternative coupling member 652 that is suitable for use with flat (i.e., flat in a transverse direction) longitudinal planks. The coupling member 652 has a first end flange 654 and a second end flange 656 separated by a vertical wall 658. A generally U-shaped channel is formed along each side of the coupling member 652, which functions in a manner like that described above with reference to the coupling member 602.

The process of extending the assembly 400 of longitudinal planks 402 continues as described above until a desired length of the host pipe 100 that is being rehabilitated is lined with longitudinal planks 402. In many cases, substantially the entire length of the host pipe 100 is lined with longitudinal planks 402. As each additional plurality of longitudinal planks 402 is installed, the individual longitudinal planks 402 are coupled to one another and are attached to the support frame 300 and optionally shimmed, as described above. For better certainty, the process of assembling the longitudinal planks 402 may be paused at various points prior to extending the assembly 400 of longitudinal planks 402 to the final desired length. For instance, as described in more detail below, after completion of approximately 30 m of the assembly 400 of longitudinal planks 402 a cementitious grout material is pumped into the just-completed section to form a grout layer 500. After pumping and at least partial curing of the grout material within the completed section, the process of extending the assembly 400 of longitudinal planks 402 continues for another 30 m, etc.

Referring again to FIG. 4, the assembly 400 of longitudinal planks 402 is formed such that the ends of the longitudinal planks 402 are staggered in the length direction of the host pipe 100, thereby ensuring that there is no continuous circular seam extending around the circumference of the assembly 400 of longitudinal planks 402. In the example that is shown in FIG. 4, adjacent longitudinal planks 402 are staggered in the length direction by approximately one half the length of the longitudinal planks 402. Of course, adjacent longitudinal planks 402 may be staggered by a different amount, such as for instance one third or one quarter of the length of the longitudinal planks 402, etc.

After a section of the assembly 400 of longitudinal planks 402 has been assembled, such as for instance a 30 m section of the assembly, secured to the support frame 300, and optionally shimmed, a grout layer 500 is formed by pumping a grout material into the annular space between the assembly 400 of longitudinal planks 402 and the preparation treatment 200 that is applied to the inner surface of the host pipe 100. For instance, 20 mm grout hoses are wrapped at 45-degree angles through the interior of the host pipe. Two hoses may be used, one installed with a right (spiral) lay and one left (spiral) lay. Pumping is done through an inflatable bulkhead. The bulkhead is preferably installed at the 10 o'clock and 2 o'clock positions. Entry points are preferably at the 4 o'clock and 7 o'clock positions of the bulkhead. Valves control a ‘T’ in the grout hoses. Grouting will take 2 hours to complete a 30 m section. The grout material fills the annular space between the assembly 400 of longitudinal planks 402 and the preparation treatment 200. By way of a specific and non-limiting example, VELOSIT® NG 511 or an equivalent grouting solution is pumped into the annular space to form the grout layer 500. VELOSIT® NG 511 has minimal shrinkage, has slight volume increase in the plastic stage to ensure good bonding to metal, has corrosion inhibitor, adequate working time (60-minute working time) and 1740 psi (12 MPa) compressive strength after 6 hours, excellent adhesion to properly prepared concrete and steel, and minimal water penetration. As noted above, in host pipes 100 having a length greater than 30 m, the pumping of the grout takes place in multiple stages as groups of the longitudinal planks 402 are inserted. By way of a specific and non-limiting example, as discussed above, approximately 30 m of the assembly 400 of longitudinal planks 402 may be installed, including the pumping of grout material, per day. Additional segments of 30 m or less may be installed during subsequent days until the full length of the host pipe 100, or at least a predetermined portion thereof, has been rehabilitated.

The grout layer 500 bonds to and extends from the preparation treatment 200 to the surface 404 of the longitudinal planks 402 in the assembly 400 of longitudinal planks 402. Due to the interconnection of the longitudinal planks 402 via the male coupling rail 406 and the female coupling groove 408, and the use of appropriate end connectors 602 or 652, the grout material does not leak through the assembly 400 of longitudinal planks 402. The pumped-in grout material therefore can fill entirely or substantially entirely the annular space that is defined between the preparation treatment 200 and the assembly 400 of longitudinal planks 402. As shown in FIG. 7A and FIG. 7B, the pumped-in grout material flows around the rod-elements 302 and 308 and hoop-elements 304 of the support frame 300, such that the support frame 300 becomes entirely or substantially entirely embedded in the grout layer 500 upon curing of the grout material. Similarly, the grout material flows around the longitudinal protrusions from the face 404 of the longitudinal planks 402, such as for instance the T-shaped longitudinal protrusions 410 a, 410 b and 410 c, as well as the clips 1300 and optional sliding-block wedges 1400 if present, all of which also become embedded in the grout layer 500 upon curing of the grout material.

As will be apparent, the grout layer 500 serves to fix the components of the system shown in FIGS. 1A and 1B in place within the host pipe 100. In the instant example, each longitudinal plank 402 has three T-shaped longitudinal protrusions extending continuously from one end of the longitudinal plank to the opposite end of the longitudinal plank. When the three T-shaped longitudinal protrusions are embedded in the cured cementitious grout material of the grout layer 500, a very secure and permanent connection is made and any further movement of the individual longitudinal planks 402 or of the assembly 400 of longitudinal planks is unlikely without first breaking up the grout layer 500.

In an alternative implementation, the assembly of longitudinal planks 402 may extend circumferentially only part of the way around the inside of the host pipe 100. For instance, a trough-shaped assembly of longitudinal planks 402 may be installed within approximately the bottom half of the host pipe 100. In this case, the grout material is pumped into a generally U-shaped space between the assembly of longitudinal planks 402 and the preparation treatment 200 applied to the inner surface of the host pipe 100. Alternatively, if the host pipe 100 is an arch shaped structure rather than a full cylinder host pipe, then a substantially arch shaped assembly of longitudinal planks 402 may be constructed and the grout material may be pumped into a generally inverted U-shaped space between the assembly of longitudinal planks 402 and the preparation treatment 200 applied to the inner surface of the host pipe 100.

FIG. 8A is an isometric view of a system according to another embodiment, shown in an installed condition within a host pipe 100 in the form of a corrugated steel tube. FIG. 8B is a corresponding end view of the system that is shown in FIG. 8A. Although it is not shown explicitly in FIG. 8A or FIG. 8B, the host pipe 100 is partially buried in the ground and is surrounded typically by soil, clay, or an aggregate material such as for instance sand and/or gravel. For example, the host pipe 100 may be installed substantially horizontally beneath a not-illustrated highway, with the opposite ends thereof projecting from the roadbed, for providing water drainage under the highway or for providing a wildlife corridor, etc. The size of the host pipe 100 may be in a range from less than a meter to several meters in diameter with typical lengths that are greater than several meters. A very long host pipe 100, having a length greater than e.g., 10 meters, may be fabricated using a series of shorter pipe-sections that are connected in an end-to-end fashion to provide a desired final length. The method and system described herein is equally suited for use with host pipes that are fabricated from either a single length of pipe or several connected lengths of pipe.

Installation of the system that is shown in FIG. 8A and FIG. 8B is performed with the host pipe 100 remaining in place, resulting in a new liner being formed within the pre-existing host pipe 100. Since the host pipe 100 is not removed or broken during the installation process, the disruption to vehicle traffic, wildlife, and the surrounding environment is minimized. Advantageously, the system that is shown in FIG. 8A and FIG. 8B provides mechanical support to prevent partial collapse or total failure of the pre-existing host pipe 100, whilst also minimizing or eliminating further erosion around the host pipe 100. Once installed, the system that is shown in FIG. 8A and FIG. 8B may extend the useful life of the host pipe 100 by an additional 75 years by providing wall restoration, waterproofing, and/or abrasion resistance.

Referring still to FIG. 8A and FIG. 8B, the system according to the instant embodiment includes different components, which may be envisaged as being arranged in distinct layers that are assembled within the pre-existing host pipe 100 in a series of steps. The number of these different components and their specific configuration may vary depending upon the type of host pipe 100 that is being rehabilitated, the condition of the host pipe 100, and the size of the host pipe 100, etc.

Prior to rehabilitating the host pipe 100, the surrounding site conditions should be surveyed to identify abnormalities or additional problems that may exist on site and appropriate remediation steps should be taken. Optionally but preferably, a LIDAR (Light Detection and Ranging) survey should be conducted to record initial conditions to be compared with conditions that are measured after rehabilitation is complete. Key survey points to be studied are at, for example, 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock positions within the host pipe 100. Of course, different positions and/or additional positions may be surveyed.

After completing the initial survey, for best results, the inner surface of the host pipe 100 is cleaned using e.g., high pressure water blasting to remove bond breaking substances disposed thereon. For instance, a water pressure of at least 3000 psi and more preferably at least 5000 psi may be used for the initial cleaning step.

In this specific and non-limiting example, a preparation treatment 200 is applied to an inner surface of the host pipe 100. The preparation treatment 200 has already been discussed above with reference to FIGS. 2A to 2C. Briefly, the preparation treatment 200 at least partially fills the inner corrugations or indents along the inner surface of the host pipe 100, and it may be applied around the entire inner circumference of the inner surface of the host pipe or optionally to only a portion of the inner circumference of the inner surface, such as for instance between about the 5 o'clock position to about the 7 o'clock position.

The preparation treatment 200 may include a plurality of different materials, which are applied in a plurality of separate layers. As discussed above, in the specific example that is shown in FIG. 2C, a layer of closed cell foam 204 is applied initially to the inner surface of the host pipe 100. Preferably, the inside diameter of the host pipe 100 is substantially uniform along the length thereof after application of the closed cell foam 204. The term “substantially uniform” in this context means more uniform than the diameter of the host pipe before applying the closed cell foam 204, since the corrugation indents are at least partially filled in. Preferably 80% to 100% of the depth of corrugation indents of the inner surface of host pipe 100 are filled in after this step, and more preferably the layer of closed cell foam is screeded to a substantially circular cross-section. A layer of a mortar material 206, such as for instance repair mortar VELOSIT® RM 202, is then applied on top of the closed cell foam 204 using a trowel or another suitable applicator. Finally, in the instant example, a waterproof layer 208, such as for instance VELOSIT® WP 120, is applied. As shown in FIG. 2C, a gauge pin 210 may be installed prior to application of the above-mentioned layers of material to guide the application and screeding of the closed cell foam 204. The thickness of the layer of closed cell foam 204 varies along the length of the host pipe 100 due to the irregular shape of the inner surface of the corrugated material of the host pipe 100. Suitable thicknesses of the layers of repair mortar layer and of the waterproof layer are approximately 6 mm and 2 mm, respectively.

In an alternative implementation, the preparation treatment 200 may be formed entirely from the repair mortar VELOSIT® RM 202 or another suitable material, optionally with a waterproof layer applied on top thereof. The repair mortar or other suitable material in this case serves to fill in the corrugation indents and to provide the bonding surface to which another cementitious grout material can adhere during subsequent steps of the installation process. Advantageously, the layer of repair mortar or other suitable material filling the corrugation indents is structurally strong and increases support within sections of the host pipe 100 that are badly corroded or damaged.

The system shown in FIG. 8A and FIG. 8B further includes a support frame 900, which is shown in isolation in FIG. 9A. The support frame 900 is a less labor-intensive system to install compared to the rod-and-hoop support frame 300 that has been discussed above. Support frame 900 may be erected in a very short amount of time by two workers with no welding required. The support frame 900 uses two separate lengths 902 and 904 of fiber reinforced polymer (FRP) rebar, which comes in many forms. For instance, the FRP rebar can be made of Basalt fiber, glass fiber, or carbon fiber. Notwithstanding, all these FRP rebars have similar characteristics that makes them suitable for use in the support frame 900. In particular, the lengths 902 and 904 of FRP rebar used to make the support frame 900 should have adequate tensile strength, be lightweight, and be resistant to corrosion. Longer lengths of these FRP rebar types bend easily but are resilient and spring back from a bent form when released. That said, if the bend radius is too small, the FRP rebar will be damaged so care must be taken to ensure that the bend radius is suitable for the size and type of FRP rebar. The resilience of FRP rebar is not found in typical steel rebar and is useful when positioning a length from a large diameter coil to form spiral. For example, when steel rebar is bent, it remains bent. However, basalt rebar when bent or coiled and then fully released will spring back to a nearly straight form. If the basalt rebar is coiled and released from being held in a coil it will uncoil itself.

Referring still to FIG. 9A, the support frame 900 may be fabricated from two lengths 902 and 904 of 8 mm FRP rebar, preferably 8 mm basalt rebar. The lengths 902 and 904 of FRP rebar are inserted into the host pipe 100, preferably with the pretreatment 200 applied to the inner surface thereof. A first end of one length 902 of FRP rebar is secured at a 3 o'clock position at the far end of the host pipe 100, relative to an operator, for instance using an anchor 906 that is similar to the resilient anchoring fasteners 202 described above. Similarly, a first end of the other length 904 of FRP rebar is secured at a 9 o'clock position at the far end of the host pipe 100, for instance using another anchor 906. The operator holds the opposite second ends of the lengths 902 and 904 of FRP rebar while the first ends are being secured. The operator then pushes both lengths 902 and 904 of FRP rebar into the host pipe 100 with moderate force, thereby interlacing the lengths 902 and 904 of FRP rebar into two spirals. As shown in FIG. 9A, additional anchors 906 are used to secure the two spirals of FRP rebar to the inner surface of the host pipe 100.

It should be noted that by interlacing the lengths 902 and 904 of FRP rebar they alternately cross over each other—length 902 crossing over length 904 and then length 904 crossing over length 902, etc. Plastic clips or ties 908 are installed during creation of the support frame 900 to secure the lengths 902 and 904 of FRP rebar and to couple together the portions which cross over each other, as shown most clearly in FIG. 9B.

It should be noted that although preferably two separate lengths 902 and 904 of FRP rebar are used, it is possible to use a single length of FRP rebar where the middle of the length is secured at one end of the host pipe 100 and the two lengths on either side of the secured-middle overlap each other in spirals, one overlapping with the other in an alternating pattern.

The support frame 900, in a manner similar to support frame 300 as discussed above, provides a plurality of attachment points along a curved plane that is spaced away from the inner surface of the host pipe 100. As shown in FIG. 8B, the spacing between the support frame 900 and the preparation treatment 200 on the inner surface of the host pipe 100 may be substantially uniform in the circumferential direction. Alternatively, the spacing may vary in the circumferential direction as described above and optionally a larger space at the bottom of the host pipe 100 is partially filled by a layer of cement.

Now referring also to FIG. 12, the system that is shown in FIG. 8A and FIG. 8B further includes an assembly 1200 of longitudinal planks 1202, which is similar to the assembly 400 of longitudinal planks 402 described above. The assembly 1200 of longitudinal planks 1202 is secured to the support frame 900 via the plurality of attachment points. As shown in FIG. 8A, the assembly 1200 of longitudinal planks 1202 includes a plurality of individual planks 1202 each having dimensions of, for instance, 1.2 m (4 feet) in length by 23 cm (9 inches) in width or 1.2 m (4 feet) in length by 30 cm (12 inches) in width, with a thickness of about 4 mm (0.15 inches). Of course, the longitudinal planks 1202 may have dimensions that differ from these specific and non-limiting examples, which have been selected to provide longitudinal planks that are of a manageable size such that one worker may lift, carry and install the longitudinal planks 402 as well as to allow the longitudinal planks 402 to be passed through narrow spaces or around obstacles and corners, etc. The longitudinal planks 1202 are fabricated from a suitable material, which is preferably light-weight, for example a plastic or recycled plastic, such as for instance a high-density polyethylene (HDPE), using a suitable process, such as for instance an extrusion process.

As shown most clearly in FIG. 12, each longitudinal plank 1202 has a first face 1204 and has a male coupling rail 1206 formed along one longitudinal edge and a complementary female coupling groove 1208 formed along an opposite longitudinal edge. When in an installed condition, the first face 1204 is oriented facing toward the inner surface of the host pipe 100. Each longitudinal plank 1202 has at least a protrusion extending from the first face 1204. The protrusions perform several functions and may be provided in a variety of forms. For example, the protrusions may be provided as generally T-shaped longitudinal protrusions 1210 a and 1210 b as shown in FIG. 12. Although two longitudinal protrusions are shown in FIG. 12, optionally the number of longitudinal protrusions may be less than two or greater than two. In addition, other protrusion profiles may be provided, such as for instance Y-shaped longitudinal protrusions or arrow-shaped longitudinal protrusions. In general, the longitudinal protrusions have a narrow cross-sectional profile proximate the first face 1204 and a wide cross-sectional profile at some distance spaced away from the first face 1204, wherein the cross-section is taken in a plane normal to the longitudinal direction of the longitudinal planks 1202. In FIG. 12 each of the longitudinal protrusions 1210 a and 1210 b, which are T-shaped, extends continuously between the two opposite ends of the longitudinal plank 1202. Optionally one or more of the longitudinal protrusions is set back from one or both of the two opposite ends of the longitudinal plank 1202. Further optionally, one or more of the longitudinal protrusions is not continuous along the length of the longitudinal plank 1202, e.g., there are gaps between portions of the longitudinal protrusions.

The number, size, shape and orientation of the longitudinal protrusions is selected to be suitable for attaching the longitudinal planks 1202 to the support frame via clips or other suitable fasteners, and for allowing cementitious grout material to flow around and embed the longitudinal protrusions therein after the cementitious grout material has cured, and to increase the torsional and/or longitudinal rigidity of the longitudinal planks 1202 to resist movement and shifting during installation.

During installation of the system according to the instant embodiment, individual longitudinal planks 1202 are placed side-by-side, with the male coupling rail 1206 at the edge of one plank inserted into and coupled with the complementary female coupling groove 1208 at the edge of an adjacent longitudinal plank 402, as shown in FIG. 11. The longitudinal male coupling rail 1206 slides into the longitudinal recess of the female coupling groove 1208 to form a grout-tight seal between the two longitudinal planks 1202. The longitudinal planks are “locked” together when they are coupled in this fashion. However, the longitudinal planks can be “unlocked,” if necessary, before they are grouted in place by relatively sliding the longitudinal planks 1202 in a reverse direction.

As shown most clearly in FIG. 11, an opposite face 1212 of each longitudinal plank 1202 is substantially smooth. The substantially smooth opposite face 1212 forms an inner liner-surface of the rehabilitated host pipe 100, and the smooth texture advantageously promotes flow of water within the host pipe 100 and avoids accumulation of debris such as plastic or paper litter, plant matter etc., due to the relative lack of liner surface features.

In the instant example, the longitudinal planks 1202 are curved in a direction transverse to their length. Since the cross-section of the assembly 1200 of interconnected longitudinal planks 1202 installed within the host pipe 100 will form substantially a circle, it is advantageous for the longitudinal planks 1202 to have a slight curve conforming approximately to the curved wall of the host pipe 100, especially if the host pipe 100 is only a few meters or less in diameter. Alternatively, the longitudinal planks 1202 are substantially flat and result in a polygon like cross-sectional profile that merely approximates a circle, especially when the diameter of the host pipe 100 is more than a few meters in diameter.

The assembly 1200 of the longitudinal planks 1202 may be built in stages, after the support frame 900 has been partially or fully assembled and suitably anchored inside the host pipe 100. A first plurality of the longitudinal planks 1202 are fastened to some of the plurality of attachment points provided along the support frame 900. For instance, each attachment point is provided using a clip 1300, which is shown in isolation in FIG. 13. A first recessed portion 1302 of the clip 1300, which is generally circular in shape, is used to secure the clip 1300 to one of the lengths 902 or 904 of FRP rebar of the support frame 900. A second recessed portion 1304 of the clip 1300 is shaped to receive the free end of one of the T-shaped longitudinal protrusions 1210 a or 1210 b of one of the longitudinal planks 1202, thereby forming a connection between the longitudinal plank 1202 and the support frame 900. Of course, the clip 1300 may be modified to connect different sized FRP rebar and/or different shaped longitudinal protrusions carried by the longitudinal planks 1202. Advantageously, since the second recessed portion 1304 of the clip 1300 allows the clip 1300 to slide along the longitudinal protrusions on the longitudinal planks 1202, the points of attachment between the longitudinal planks 1202 and the support frame 900 can be adjusted to ensure that an adequate number of attachments are made, even if the support frame 900 is not built precisely to the expected specifications and/or the assembly 1200 of longitudinal planks 1202 is not correctly aligned within the host pipe 100. In particular, the clip 1300 may be moved along the respective longitudinal protrusion to a point at which the first recessed portion 1302 is aligned with a suitable one of the lengths 902 or 904 of FRP rebar of the support frame 900.

Sliding-block wedges 1400, which are shown in isolation in FIG. 14A and 14B, are positioned between the assembly 1200 of longitudinal planks 1202 and the support frame 900 or preparation treatment 200 on the inner surface of the host pipe 100. Each sliding-block wedge 1400 includes a body 1402 and a sliding wedge 1404, which slide relative to one another along an inclined plane P_(incl), as is shown most clearly in FIG. 14 B in a cross-section taken in the plane P_(cross) indicated in FIG. 14A. The body 1402 also has a channel 1406 that is sized to receive one of the T-shaped protrusions 1210 a or 410 b on the surface 1204 of one of the longitudinal planks 1202. Moving the sliding wedge 1404 relative to the body 1402 changes the effective thickness of the sliding-wedge block 1400 since the movement occurs along the inclined plane P_(incl). The sliding-block wedges may be disposed at different circumferential and longitudinal locations between e.g., the support frame 900 and the assembly 1200 of longitudinal planks 1202, to effectively shim the assembly 1200 of longitudinal planks 1202 in place. The sliding-block wedges 1400 also function to adjust the space that is defined between the assembly 1200 of longitudinal planks 1202 and the preparation layer 200, and to prevent movement of the assembly 1200 of longitudinal planks 1202 during subsequent steps in which a grout material is pumped into said space.

Of course, the sliding-block wedges 1400 may be omitted if the longitudinal planks 1202 can be secured to the support frame 900 with sufficient rigidity to avoid significant movement or shifting during introduction of the cementitious grout material during subsequent steps. Alternatively, expanding ring-shaped support members or other suitable reinforcement members may be temporarily installed within the assembly 1200 of longitudinal planks to maintain a desired cross-sectional shape of the assembly 1200 during introduction of the cementitious grout material. Once the grout material has cured, and the assembly 1200 of longitudinal planks is locked into the desired configuration, the temporary support members may be removed. Further, the longitudinal planks 1202 may be attached to the support frame 900 using other fasteners or differently configured clips.

Referring again to FIG. 8A, a second plurality of the longitudinal planks 1202 are then butted up against the ends of the first plurality of the longitudinal planks 1202 and are secured to the support frame 900, so as to extend the length of the assembly 1200 of longitudinal planks 1202. A suitable end-coupling member is disposed between the ends of each longitudinal plank 1202 of the first plurality of longitudinal planks 402 and the ends of each longitudinal plank 1202 of the second plurality of longitudinal planks 1202.

FIG. 6A shows detail of an end-coupling member 602 that is suitable for use with longitudinal planks 1202 that are transversely curved, e.g., of the type that is shown in FIG. 8A, FIGS. 10-10B, FIG. 11 and FIG. 12. The coupling member 602 has a first end flange 604 and a second end flange 606 separated by a vertical wall 608. A generally U-shaped channel is formed along each side of the coupling member 602. When the coupling member 602 is disposed between the ends of two longitudinal planks 1202, the end of one of the longitudinal planks 1202 is received within the channel on one side of the coupling member 602 and the end of the other one of the longitudinal planks 1202 is received within the channel on the other side of the coupling member 602.

FIG. 6B shows detail of an alternative coupling member 652 that is suitable for use with flat (i.e., flat in a transverse direction) longitudinal planks. The coupling member 652 has a first end flange 654 and a second end flange 656 separated by a vertical wall 658. A generally U-shaped channel is formed along each side of the coupling member 652, which functions in a manner like that described above with reference to the coupling member 602.

The process of extending the assembly 1200 of longitudinal planks 1202 continues as described above until a desired length of the host pipe 100 that is being rehabilitated is lined with longitudinal planks 1202. In many cases, substantially the entire length of the host pipe 100 is lined with longitudinal planks 1202. As each additional plurality of longitudinal planks 1202 is installed, the individual longitudinal planks 1202 are coupled to one another and are attached to the support frame 900 and shimmed, as described above. For better certainty, the process of assembling the longitudinal planks 1202 may be paused at various points prior to extending the assembly 1200 of longitudinal planks 1202 to the final desired length. For instance, as described in more detail below, after completion of approximately 30 m of the assembly 1200 of longitudinal planks 1202 a cementitious grout material is pumped into the just-completed section to form a grout layer 500. After pumping and at least partial curing of the grout material within the completed section, the process of extending the assembly 1200 of longitudinal planks 1202 continues for another 30 m, etc.

Referring again to FIG. 8A, the assembly 1200 of longitudinal planks 1202 is formed such that the ends of the longitudinal planks 1202 are staggered in the length direction of the host pipe 100, thereby ensuring that there is no continuous circular seam extending around the circumference of the assembly 1200 of longitudinal planks 1202. In the example that is shown in FIG. 8A, adjacent longitudinal planks 1202 are staggered in the length direction by approximately one half the length of the longitudinal planks 1202. Of course, adjacent longitudinal planks 1202 may be staggered by a different amount, such as for instance one third or one quarter of the length of the longitudinal planks 1202.

After a section of the assembly 1200 of longitudinal planks 1202 has been assembled, such as for instance a 30 m section of the assembly, secured to the support frame 1200, and shimmed, a grout layer 500 is formed by pumping a grout material into the annular space between the assembly 1200 of longitudinal planks 1202 and the preparation treatment 200 that is applied to the inner surface of the host pipe 100. For instance, 20 mm grout hoses are wrapped at 45-degree angles through the interior of the host pipe. Two hoses may be used, one installed with a right (spiral) lay and one left (spiral) lay. Pumping is done through an inflatable bulkhead. The bulkhead is preferably installed at the 10 o'clock and 2 o'clock positions. Entry points are preferably at the 4 o'clock and 7 o'clock positions of the bulkhead. Valves control a ‘T’ in the grout hoses. Grouting will take 2 hours to complete a 30 m section. The grout material fills the annular space between the assembly 1200 of longitudinal planks 1202 and the preparation treatment 200. By way of a specific and non-limiting example, VELOSIT® NG 511 or an equivalent grouting solution is pumped into the annular space to form the grout layer 500. VELOSIT® NG 511 has minimal shrinkage, has slight volume increase in the plastic stage to ensure good bonding to metal, has corrosion inhibitor, adequate working time (60-minute working time) and 1740 psi (12 MPa) compressive strength after 6 hours, excellent adhesion to properly prepared concrete and steel, and minimal water penetration. As noted above, in host pipes 100 having a length greater than 30 m, the pumping of the grout takes place in multiple stages as groups of the longitudinal planks 1202 are inserted. By way of a specific and non-limiting example, as discussed above, approximately 30 m of the assembly 1200 of longitudinal planks 1202 may be installed, including the pumping of grout material, per day. Additional segments of 30 m or less may be installed during subsequent days until the full length of the host pipe 100, or at least a predetermined portion thereof, has been rehabilitated.

The grout layer 500 bonds to and extends from the preparation treatment 200 to the surface 1204 of the longitudinal planks 1202 in the assembly 1200 of longitudinal planks 1202. Due to the interconnection of the longitudinal planks 1202 via the male coupling rail 1206 and the female coupling groove 1208, and the use of appropriate end connectors 602 or 652, the grout material does not leak through the assembly 1200 of longitudinal planks 1202. The pumped in grout material therefore can fill entirely or substantially entirely the annular space that is defined between the preparation treatment 200 and the assembly 1200 of longitudinal planks 1202. As shown in FIG. 10A, FIG. 10B and FIG. 11, the pumped-in grout material flows around the lengths 902 and 904 of FRP rebar of the support frame 900, such that the support frame 900 becomes entirely or substantially entirely embedded in the grout layer 500 upon curing of the grout material. Similarly, the grout material flows around the longitudinal protrusions from the face 1204 of the longitudinal planks 1202, such as for instance the T-shaped longitudinal protrusions 1210 a and 1210 b, as well as the clips 1300 and optional sliding-block wedges 1400 if present, all of which also become embedded in the grout layer 500 upon curing of the grout material.

As will be apparent, the grout layer 500 serves to fix the components of the system shown in FIG. 8A and 8B in place within the host pipe 100. In the instant example, each longitudinal plank 1202 has two T-shaped longitudinal protrusions 1210 a and 1210 b extending continuously from one end of the longitudinal plank 1202 to the opposite end of the longitudinal plank 1202. When the two T-shaped longitudinal protrusions 1210 a and 1210 b are embedded in the cured cementitious grout material of the grout layer 500, a very secure and permanent connection is made and any further movement of the individual longitudinal planks 1202 or of the assembly 1200 of longitudinal planks is unlikely without first breaking up the grout layer 500.

In an alternative implementation, the assembly of longitudinal planks 1202 may extend circumferentially only part of the way around the inside of the host pipe 100. For instance, a trough-shaped assembly of longitudinal planks 1202 may be installed within approximately the bottom half of the host pipe 100. In this case, the grout material is pumped into a generally U-shaped space between the assembly of longitudinal planks 1202 and the preparation treatment 200 applied to the inner surface of the host pipe 100. Alternatively, if the host pipe 100 is an arch shaped structure rather than a full cylinder host pipe, then a substantially arch shaped assembly of longitudinal planks 1202 may be constructed and the grout material may be pumped into a generally inverted U-shaped space between the assembly of longitudinal planks 1202 and the preparation treatment 200 applied to the inner surface of the host pipe 100.

Referring now to FIG. 15, shown is a simplified flow diagram of a method according to an embodiment of the instant invention. At step 1500 the inner surface of the host pipe is cleaned, such as for instance by high pressure water blasting to remove bond breaking substances on the inner surface. By way of an example, the inner surface of the host pipe is cleaned using a pressure washer at 3000-5000 psi (5000 psi preferred). As much as is possible, all dust and debris is removed from areas to be treated, anchored or supported.

At step 1502, a preparation treatment is applied to the inner surface of the host pipe. The preparation treatment includes one or more layers of materials that are selected to provide a good support and bonding. By way of a specific and non-limiting example a layer of closed cell foam is applied initially to the inner surface of the host pipe. Preferably, the inside diameter of the host pipe is substantially uniform along the length thereof after application of the closed cell foam, which in this context means more uniform than the diameter of the host pipe before applying the closed cell foam. By way of an example, 80% to 100% of the depth of corrugation indents of the inner surface of host pipe are filled with the closed cell foam, and more preferably the layer of closed cell foam is screeded to a substantially circular cross-section. A layer of a mortar material, such as for instance repair mortar VELOSIT® RM 202, is then applied on top of the closed cell foam using a trowel or another suitable applicator. A waterproof layer, such as for instance VELOSIT® WP 120, may then be applied to complete the preparation treatment. The thickness of the layer of closed cell foam varies due to the irregular shape of the inner surface of the corrugated material of the host pipe. Suitable thicknesses of the layers of repair mortar layer and of the waterproof layer are approximately 6 mm and 2 mm, respectively.

At step 1504 a support frame is constructed and secured to the inner surface of the host pipe. For instance, first and second lengths of FRP rebar are installed running along the inner surface of the host pipe, forming respective spirals with a right lay and a left lay beginning at the discharge end of the host pipe. The two spirals of FRP rebar run in opposite directional rotations one relative to the other, so that they cross and overlap periodically. The lengths of FRP rebar are installed in the host pipe at a 22.5-degree angle (to the horizontal) thus “spiraling.”

At step 1506 an assembly of longitudinal planks is installed and secured to the support frame so as to form a liner within the host pipe. The longitudinal planks are interconnected by male coupling rails and female coupling grooves disposed along opposite longitudinal edges thereof End connectors are disposed between the butted up against one another ends of adjacent longitudinal planks in the length direction, thereby supporting the ends of the planks and sealing spaces that would otherwise allow grout material to pass through. The ends of the longitudinal planks are staggered such that there is no seam extending circumferentially around the assembly of longitudinal planks. Various wedges and clips are used at this stage to secure the longitudinal planks to the support frame and to shim the structure, so as to put equal pressure on all points around the complete plank structure and hold it in place.

At step 1508, grout material is pumped into the annular space between the liner of longitudinal planks and the preparation treatment applied to the inner surface of the host pipe. By way of an example, 20 mm grout hoses are wrapped at 45-degree angles through the interior of the host pipe. Two hoses may be used, one installed with a right (spiral) lay and one left (spiral) lay. Pumping is done through an inflatable bulkhead. The bulkhead is preferably installed at the 10 o'clock and 2 o'clock positions. Entry points are preferably at the 4 o'clock and 7 o'clock positions of the bulkhead. Valves control a ‘T’ in the grout hoses. Grouting will take 2 hours to complete a 30 m section. By way of a specific and non-limiting example, VELOSIT® NG 511 or an equivalent grouting solution is used.

Throughout the description and claims of this specification, the words “comprise”, “including”, “having” and “contain” and variations of the words, for example “comprising” and “comprises” etc., mean “including but not limited to”, and are not intended to, and do not exclude other components.

It will be appreciated that variations to the foregoing embodiments of the disclosure can be made while still falling within the scope of the disclosure. Each feature disclosed in this specification, unless stated otherwise, may be replaced by alternative features serving the same, equivalent or similar purpose. Thus, unless stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

All of the features disclosed in this specification may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. In particular, the preferred features of the disclosure are applicable to all aspects of the disclosure and may be used in any combination. Likewise, features described in non-essential combinations may be used separately (not in combination). 

What is claimed is:
 1. A method for in situ rehabilitation of a host pipe, comprising: disposing a support frame within the host pipe and adjacent to an inner surface of the host pipe, the support frame providing a plurality of attachment points spaced away from the inner surface of the host pipe; attaching a plurality of longitudinal planks to the support frame via the plurality of attachment points, each longitudinal plank of the plurality of longitudinal planks having an inwardly facing surface that forms a portion of a liner surface within the host pipe, and each longitudinal plank of the plurality of longitudinal planks having an outwardly facing surface opposite the inwardly facing surface with at least one longitudinal protrusion extending away therefrom; and at least partially filling a space that is defined between the inner surface of the host pipe and the plurality of longitudinal planks with a cementitious grout material, to form a grout layer upon curing of the cementitious grout material, wherein the cementitious grout material flows around and surrounds the at least one longitudinal protrusion during the step of filling the space, such that the at least one longitudinal protrusion is embedded within the grout material upon curing of the cementitious grout material.
 2. The method of claim 1, wherein disposing the support frame within the host pipe comprises forming two overlapping spirals of a fiber reinforced polymer (FRP) rebar material within the host pipe, one of the two overlapping spirals of FRP rebar having a right lay and the other one of the two overlapping spirals of FRP rebar having a left lay.
 3. The method of claim 1, wherein disposing the support frame within the host pipe comprises assembling together a plurality of rod-elements and a plurality of hoop-elements.
 4. The method of claim 1, further comprising anchoring the support frame to the host pipe.
 5. The method of claim 1, wherein attaching each longitudinal plank of the plurality of longitudinal planks to the support frame comprises: attaching clips to the support frame to define attachment points of the plurality of attachment points; and slidingly receiving the at least one protrusion extending from the outwardly facing surface of the longitudinal plank within complementary shaped-recess portions of the clips.
 6. The method of claim 5, wherein attaching each longitudinal plank of the plurality of longitudinal planks to the support frame further comprises engaging a first coupling structure arranged along a first longitudinal edge of a longitudinal plank with a second coupling structure arranged along a second longitudinal edge of an adjacent second longitudinal plank and sliding the first longitudinal plank relative to the adjacent second longitudinal plank along a longitudinal direction.
 7. The method of claim 6, wherein the plurality of longitudinal planks comprises two longitudinal planks in an end-to-end arrangement and comprising disposing an end-coupling member between the respective ends of the two longitudinal planks.
 8. The method of claim 1, comprising, prior to disposing the support frame within the host pipe: cleaning an inner surface of the host pipe using high pressure water blasting; and applying a preparation treatment to the cleaned inner surface of the host pipe.
 9. The method of claim 8, wherein the preparation treatment comprises a layer of closed cell foam material applied onto and filling recessed areas along the inner surface of the host pipe, a layer of a cementitious mortar material applied onto the layer of closed cell foam material, and a layer of a waterproof material applied onto the cementitious mortar.
 10. A method for in situ rehabilitation of a host pipe in the form of a corrugated culvert or other conduit, comprising: applying a preparation treatment to an inner surface of the host pipe to at least partially fill in at least some corrugated indentations in the inner surface of the host pipe; disposing a support frame within the interior of the host pipe and adjacent to the host pipe inner surface, and coupling said support frame to the host pipe; assembling a plurality of longitudinal planks within the interior of the host pipe to form a liner, comprising attaching the longitudinal planks to the support frame and further comprising coupling together adjacent longitudinal planks via coupling structures that are arranged along each of the opposite longitudinal edges of each of the longitudinal planks, wherein each longitudinal plank has an inwardly facing surface that forms a portion of an inner surface of the liner and an opposite outwardly facing surface having at least one longitudinal protrusion extending away therefrom; and, at least partially filling a space that is defined between the preparation treatment applied to the inner surface of the host pipe and the assembled plurality of longitudinal planks with a cementitious grout material, to form a grout layer upon curing of the cementitious grout material, wherein the cementitious grout material flows around and surrounds the at least one longitudinal protrusion during the step of filling the space, such that the at least one longitudinal protrusion is embedded within the grout material upon curing of the cementitious grout material.
 11. The method of claim 10, wherein disposing the support frame within the host pipe comprises forming two overlapping spirals of a fiber reinforced polymer (FRP) rebar material within the host pipe, one of the two overlapping spirals of FRP rebar having a right lay and the other one of the two overlapping spirals of FRP rebar having a left lay.
 12. The method of claim 10, wherein attaching each longitudinal plank to the support frame comprises: attaching clips to the support frame to provide attachment points; and slidingly receiving the at least one protrusion extending from the outwardly facing surface of the longitudinal plank within complementary shaped-recess portions of the clips.
 13. The method of claim 12, wherein the coupling structures comprise a male coupling rail disposed along a first longitudinal edge of each longitudinal plank and a female coupling groove disposed along a second longitudinal edge of each longitudinal plank opposite the first longitudinal edge, and further comprising engaging the male coupling rail disposed along the first longitudinal edge of a first longitudinal plank with the female coupling groove disposed along the second longitudinal edge of an adjacent second longitudinal plank, and sliding the first longitudinal plank relative to the adjacent second longitudinal plank along a longitudinal direction.
 14. The method of claim 10, comprising, prior to disposing the support frame within the host pipe, cleaning an inner surface of the host pipe using high pressure water blasting, wherein the preparation treatment is applied to the cleaned inner surface of the host pipe.
 15. The method of claim 14, wherein the preparation treatment comprises a layer of closed cell foam material applied onto and filling recessed areas along the inner surface of the host pipe, a layer of a cementitious mortar material applied onto the layer of closed cell form material, and a layer of a waterproof material applied onto the cementitious mortar.
 16. A system for in situ rehabilitation of a host pipe in the form of a corrugated culvert or other conduit, comprising: a support frame, which is sized for being received within and coupled to an inner surface of the host pipe, the support frame configured to provide a plurality of attachment points spaced away from the inner surface of the host pipe; a plurality of interconnected longitudinal planks forming a liner within the host pipe, each longitudinal plank of the plurality of longitudinal planks having an inwardly facing surface that forms a portion of an inner surface of the liner, and each longitudinal plank of the plurality of longitudinal planks having an outwardly facing surface opposite the inwardly facing surface with at least one longitudinal protrusion extending away therefrom; and a layer of a cured cementitious grout material filling or substantially filling a space between the inner surface of the host pipe and the plurality of interconnected planks, wherein the at least one longitudinal protrusion of each longitudinal plank is embedded within the cured cementitious grout material.
 17. The system of claim 16, further comprising a preparation treatment applied to the inner surface of the host pipe, the preparation treatment comprising: a layer of closed cell foam material applied onto and filling recessed areas along the inner surface of the host pipe; a layer of a cementitious mortar material applied onto the layer of closed cell foam material; and a layer of a waterproof material applied onto the cementitious mortar.
 18. The system of claim 16, wherein the support frame comprises two overlapping spirals of a fiber reinforced polymer (FRP) rebar material, one of the two overlapping spirals of FRP rebar having a right lay and the other one of the two overlapping spirals of FRP rebar having a left lay.
 19. The system of claim 16, wherein the support frame comprises a plurality of rod-elements and a plurality of hoop-elements, the hoop elements being spaced apart from one another along a length direction of the support frame, and each of the rod elements being coupled to the hoop elements, wherein the rod elements are arranged circumferentially around the hoop elements.
 20. The system of claim 16, wherein each longitudinal plank of the plurality of interconnected longitudinal planks comprises: a male coupling rail disposed along a first longitudinal edge thereof; and a female coupling groove disposed along a second longitudinal edge thereof opposite the first longitudinal edge, wherein a first longitudinal plank is interconnected with an adjacent second longitudinal plank by engaging the male coupling rail disposed along the first longitudinal edge of the first longitudinal plank with the female coupling groove disposed along the second longitudinal edge of the adjacent second longitudinal plank, and sliding the first longitudinal plank relative to the adjacent second longitudinal plank along a longitudinal direction.
 21. The system of claim 16, comprising a plurality of clips, each clip having a first recessed portion configured to attach to the support frame to define one attachment point of the plurality of attachment points and having a second recessed portion configured to slidingly receive the at least one protrusion extending from the outwardly facing surface of one of the longitudinal planks.
 22. The system of claim 16, wherein the plurality of interconnected longitudinal planks comprises two longitudinal planks in an end-to-end arrangement and comprising an end-coupling member disposed between the respective ends of the two longitudinal planks in the end-to-end arrangement.
 23. A rehabilitated culvert, comprising: a corrugated steel pipe (CSP) having an outer corrugated surface and an inner corrugated surface; a preparation treatment applied to the inner corrugated surface; a layer of cured cementitious grout material bonded to the preparation treatment; a support frame embedded within the layer of the cementitious grout material; and a plurality of interconnected longitudinal planks arranged side-by-side and end-to-end, each longitudinal plank having at least one longitudinal protrusion on a surface thereof facing the inner corrugated surface, the at least one longitudinal protrusion of each longitudinal plank being imbedded within the layer of cured cementitious grout material, the interconnected longitudinal planks cooperating to form an inside liner of the CSP that is spaced away from the inner corrugated surface of the CSP.
 24. The rehabilitated culvert of claim 23, wherein the preparation treatment comprises: a layer of closed cell foam material applied onto and filling recessed areas along the inner corrugated surface; a layer of a cementitious mortar material applied onto the layer of closed cell foam material; and a layer of a waterproof material applied onto the cementitious mortar 